This invention relates to mold structures and methods for molding and, more particularly, to mold structures and methods for molding a remote attachment member to a sheet or panel of material, for example glass, to form a modular vehicle component assembly for applications including window assemblies, decorative trim assemblies, and the like.
In recent years the manufacturing of automobiles and other vehicles has included the use of light weight, strong, modular panel assemblies which are made and installed as a single unit in the vehicle. For example, newer modular window assemblies include a window panel with a gasket molded around the periphery of the window panel and may further include fasteners molded with the gasket to provide a means for attaching the window assembly to the vehicle. Recent trends in body styling preferably include the window assembly mounted flush with the body of the vehicle. The resulting assembly requires much less labor for installation than has been previously known. Examples of this type of modular window assembly are shown in U.S. Pat. Nos. 4,072,340 and 4,139,234. Generally, these assemblies include a sheet of glass and a peripheral casing or gasket of molded polymeric material which extends around at least portions of the periphery of the glass.
The production of such modular window assemblies requires the combination of a sheet of glass and a polymeric gasket. The glass is configured to cover the shape of an opening in a vehicle, such as a windshield opening, a back light opening, or a side view opening as well as being curved to the contour of the overall vehicle body shape. The gasket or casing must be formed and adhered to a portion of the glass such that its periphery provides at least a secondary seal and also provides appropriate trim or body filling portions to meet required appearance standards. The gasket or casing is typically applied to the periphery or another portion of the glass sheet by reaction injection molding or PVC molding. One significant problem frequently encountered in molding gaskets and fasteners is the breakage of glass when the mold sections used to make such assemblies are closed under clamp tonnage. Curved and contoured panels inherently include a relatively wide range of piece to piece variation in their contour. Consequently, when rigid mold sections are closed around a sheet having a greater variation in contour than the mold permits, such sheet may be bent beyond its fracture point or be broken, chipped, damaged, or otherwise made unsuitable for use. This is especially true for window panels which incorporate fasteners into the gasket or, in preferred form, include remotely located fasteners.
During the molding process of curved panels, greater variations in the glass panel occur in the central region of the sheet than in the peripheral portion of the sheet. Therefore, molding apparatuses typically hold the sheet adjacent the peripheral portion of the sheet where the sheet to sheet variations are significantly smaller and can be absorbed by the molding apparatus. However where molded attachments are desired remote from the peripheral portion of the sheet or gasket, this necessarily increases the area of contact and between the molding apparatus and the sheet and extends the area of contact inwardly of the peripheral portion of the sheet toward the central region where greater sheet to sheet variations occur. With this increased and extended contact area, the glass sheets tend to exhibit increased breakage and cracking.
Accordingly, there is a need for a mold assembly and method for molding a remotely located attachment member on a sheet or panel that will accommodate a greater range of dimensional variations in the sheet or panel which are typically associated with the peripheral portion of the glass sheet and, therefore, reduce the breakage of the sheets during the molding process.